Balloon catheters and methods for use

ABSTRACT

Apparatus and methods are provided for flaring a stent deployed within a branch vessel including an ostium communicating with a main vessel, a first end of the stent extending at least partially from the branch. A catheter is provided that includes a first balloon carried on its distal end, and a second balloon that includes a distal section overlying at least a portion of the first balloon and a proximal section. The catheter distal end is introduced into the main vessel and positioned through the ostium and stent into the branch until the first balloon is disposed within the stent. The first balloon is expanded to anchor the stent, and the second balloon is expanded to flare the first end of the stent. Optionally, the first balloon is expanded further, e.g., to expand the stent within the branch body lumen and/or dilate the lesion.

This application is a continuation of co-pending application Ser. No.13/602,074, filed Aug. 31, 2012, issuing as U.S. Pat. No. 9,034,025,which claims benefit of provisional application Ser. No. 61/529,890,filed Aug. 31, 2011, and is a continuation-in-part of co-pendingapplication Ser. No. 11/466,439, filed Aug. 22, 2006, and Ser. No.12/983,860, filed Jan. 3, 2011, which is a continuation of Ser. No.11/136,266, filed May 23, 2005, issued as U.S. Pat. No. 7,862,601. Theentire disclosures of these applications are expressly incorporated byreference herein.

FIELD OF THE INVENTION

The present invention relates generally to apparatus and methods fortreating stenoses, occlusions, or other lesions within a body lumen,such as an artery or other blood vessel, and, more particularly, toapparatus and methods for flaring or otherwise expanding stents deployedwithin a body lumen, such as a branch vessel including an ostiumextending from a main vessel or trunk.

BACKGROUND

Tubular endoprosthesis or “stents” have been suggested for dilating orotherwise treating stenoses, occlusions, and/or other lesions within apatient's vasculature or other body lumens. For example, aself-expanding stent may be maintained on a catheter in a contractedcondition, e.g., by an overlying sheath or other constraint, anddelivered into a target location, e.g., a stenosis within a blood vesselor other body lumen. When the stent is positioned at the targetlocation, the constraint may be removed, whereupon the stent mayautomatically expand to dilate or otherwise line the vessel at thetarget location. Alternatively, a balloon-expandable stent may becarried on a catheter, e.g., crimped or otherwise secured over aballoon, in a contracted condition. When the stent is positioned at thetarget location, the balloon may be inflated to expand the stent anddilate the vessel.

Vascular stenoses, e.g., within arteries supplying the heart, can leadto hypoflow conditions in the vessel, which may cause ischemia and/orinfarction of the organ being supplied by that vessel, e.g., the heart.Sometimes, a stenosis or other lesion may occur at an ostium orbifurcation, i.e., where a branch vessel extends from a main vessel ortrunk. In such situations, it may be difficult to visualize the lesionand/or accurately position a stent within the ostium and/or branchvessel.

Often, when the stent is deployed in such anatomy, one end of the stentmay extend out from the ostium into the main vessel, e.g., into theaorta from a coronary artery, common carotid artery, or peripheralartery. Such a position of the stent may cause difficulty in futureendoluminal interventions, e.g., reentering the branch vessel, which mayrequire recrossing the stent. In addition, there may be risk that theend of the stent extending from the ostium may cause damage toneighboring structures, such as aortic valve leaflets adjacent to theostium of a coronary vessel.

To address these problems, it has been suggested to over-expand or flarethe end of the stent extending into the main vessel, e.g., to direct theend of the stent against or closer to the wall of the ostium.Thereafter, it may be easier to recross the stent in case futureendovascular study or intervention is required. In addition, in the caseof coronary stents, flaring the end of the stent extending into theaorta may also move the end further from the aortic lumen and decreasethe risk of damage to the aortic leaflets.

Accordingly, apparatus and methods for flaring and/or otherwiseexpanding stents would be useful.

SUMMARY OF THE INVENTION

The present invention is directed to apparatus and methods for treatingstenoses, occlusions, or other lesions within a body lumen, such as anartery or other blood vessel. More particularly, the present inventionis directed to apparatus and methods for flaring and/or otherwiseexpanding stents deployed within a body lumen, such as a branch vesselincluding an ostium extending from another main vessel or trunk.

In accordance with one embodiment, a method is provided for flaring astent deployed within a branch body lumen including an ostiumcommunicating with a main body lumen, a first end of the stent extendingat least partially from the branch body lumen into the ostium and/ormain body lumen. To accomplish this, a catheter or other elongate membermay be used that includes a proximal end, a distal end, a first ballooncarried on the distal end that includes a main section when expanded,and a second balloon carried on the distal end that includes a distalsection overlying at least a portion of the main section of the firstballoon and a proximal section extending proximally from the distalsection and/or the first balloon.

The distal end of the elongate member may be introduced into the mainbody lumen, e.g., with the first and second balloons in contractedconditions. The distal end of the elongate member may be positionedthrough the ostium and stent into the branch body lumen until the mainsection is disposed within the stent and/or distally beyond the stent,e.g., using external imaging and markers on the distal end to facilitatepositioning the proximal section of the second balloon adjacent theostium.

The first balloon may be expanded to substantially anchor the stentrelative to the branch body lumen, and the proximal section of thesecond balloon may be expanded to flare the first end of the stentwithin the ostium. Optionally, after expanding the proximal section ofthe second balloon, the first balloon may be expanded further, e.g., toexpand the stent within the branch body lumen and/or dilate the lesion.

In accordance with another embodiment, a method is provided for treatinga lesion within a branch body lumen including an ostium communicatingwith a main body lumen that includes introducing a distal end of adelivery catheter into the main body lumen, the delivery catheter distalend carrying a stent in a contracted condition; positioning the deliverycatheter distal end within the branch body lumen such that a first endof the stent is disposed adjacent the ostium and a second end of thestent is disposed further within the branch body lumen; and expandingthe stent to a substantially uniform diameter such that the stentengages surrounding tissue of the branch body lumen.

Thereafter, the first end of the stent may be flared, e.g., using aflaring catheter including a proximal end, a distal end, a first ballooncarried on the flaring catheter distal end that includes a main sectionwhen expanded, and a second balloon carried on the flaring catheterdistal end that includes a distal section overlying at least a portionof the main section of the first balloon and a proximal sectionextending proximally from the distal section and/or the first balloon.The flaring catheter distal end may be introduced into the main bodylumen, and positioned through the ostium and stent into the branch bodylumen until the main section is disposed within the stent.

The first balloon may be expanded to substantially anchor the stentrelative to the branch body lumen, and the proximal section of thesecond balloon may be expanded to flare the first end of the stentwithin the ostium. Optionally, after expanding the proximal section ofthe second balloon, the first balloon may be expanded further, e.g., toexpand the stent within the branch body lumen and/or dilate the lesion.In addition or alternatively, the lesion may be dilated when the stentis expanded, e.g., to a substantially uniform diameter by the mainsection of the first balloon.

In accordance with still another embodiment, a method is provided forexpanding a stent previously deployed within a body lumen using anelongate member including a proximal end, a distal end, a first ballooncarried on the distal end that includes a substantially uniform diametermain section when expanded, and a second balloon carried on the distalend that includes a distal section overlying at least a portion of theuniform diameter section of the first balloon and a proximal sectionextending proximally from the distal section and the first balloon. Thedistal end of the elongate member may be positioned within the bodylumen until the main section is disposed within the stent, and theproximal section of the second balloon may be expanded to substantiallyanchor the elongate member distal end, and consequently, the firstballoon, relative to the stent. The main section of the first balloonmay then be expanded to expand the stent and/or dilate a lesionsurrounding the stent, the second balloon preventing axial migration ofthe distal end.

In accordance with yet another embodiment, a method is provided fortreating a stenosis within a body lumen using an elongate memberincluding a proximal end, a distal end, a first balloon carried on thedistal end that includes a substantially uniform diameter main sectionwhen expanded, and a second balloon carried on the distal end thatincludes a distal section overlying at least a portion of the uniformdiameter section of the first balloon and a proximal section extendingproximally from the distal section and the first balloon. The distal endof the elongate member may be positioned within the body lumen until themain section is disposed within the stenosis, and the proximal sectionof the second balloon may be expanded to substantially anchor theelongate member distal end relative to the stenosis. The main section ofthe first balloon may then be expanded to dilate the stenosis, thesecond balloon preventing axial migration of the distal end.

In accordance with still another embodiment, a method is provided fortreating a stenosis within a body lumen using an elongate memberincluding a proximal end, a distal end, a first balloon carried on thedistal end that includes a substantially uniform diameter main sectionwhen expanded, and a second balloon carried on the distal end adjacentthe main section of the first balloon, e.g., proximal or distal to themain section. The distal end of the elongate member may be positionedwithin the body lumen until the main section is disposed within thestenosis, e.g., such that the second balloon is positioned adjacent,i.e., proximal or distal to, the stenosis. The second balloon may thenbe expanded to substantially anchor the elongate member distal endrelative to the stenosis. The main section of the first balloon may thenbe expanded to dilate the stenosis, the second balloon preventing axialmigration of the distal end.

In accordance with yet another embodiment, a method is provided fortreating a region within a body lumen using an elongate member includinga proximal end, a distal end, a first balloon carried on the distal endthat includes a substantially uniform diameter main section whenexpanded, and a second balloon carried on the distal end that includes afirst section overlying at least a portion of the uniform diametersection of the first balloon and a second section disposed adjacent themain section of the first balloon. The distal end of the elongate membermay be positioned within the body lumen until the main section isdisposed within a treatment region, and the second section of the secondballoon may be expanded to substantially anchor the elongate memberdistal end relative to the treatment region. The main section of thefirst balloon may then be expanded to contact and treat the treatmentregion, the second balloon preventing axial migration of the elongatemember distal end.

In one embodiment, the second section of the second balloon extendsproximally from the main section of the first balloon. In anotherembodiment, the second section of the second balloon extends distallyfrom the main section of the first balloon. In yet another embodiment, asecond section may be provided proximal to the main section and a thirdsection may be provided distal to the main section, e.g., such that thesecond balloon expands both proximally and distally to the main sectionof the first balloon, e.g., substantially simultaneously. In addition oralternatively, the first section of the second balloon may extendentirely over the main section of the first balloon or may extend onlypartially over the main section.

In an exemplary embodiment, the treatment region may be a stenosiswithin a blood vessel, e.g., within a branch vessel adjacent an ostiumcommunicating with a main vessel. In another embodiment, the treatmentregion may be the site of a natural or prosthetic valve, e.g., the siteof an aortic valve.

In accordance with still another embodiment, a method is provided fortreating a valve within a body lumen of a patient using an elongatemember including a proximal end, a distal end, a first balloon carriedon the distal end that includes a substantially uniform diameter mainsection when expanded, and a second balloon carried on the distal endthat includes a first section overlying at least a portion of theuniform diameter section of the first balloon and a second sectionadjacent the main section of the first balloon. The distal end of theelongate member is positioned within the body lumen with the first andsecond balloons collapsed until the main section is disposed within avalve. The second section of the second balloon is expanded tosubstantially anchor the distal end relative to the valve, and then themain section of the first balloon is expanded to dilate leaflets of thevalve.

Other aspects and features of the present invention will become apparentfrom consideration of the following description taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate exemplary embodiments of the invention, inwhich:

FIG. 1A is a side view of an exemplary embodiment of a catheterincluding overlapping balloons for flaring and/or otherwise expanding astent previously deployed within a body lumen.

FIG. 1B is a cross-sectional detail of a distal end of the catheter ofFIG. 1A with the balloons expanded.

FIGS. 2A-2F are cross-sectional views of a patient's body including anostium communicating between a main vessel and a branch vessel, showinga method for flaring a stent previously deployed within the branchvessel using the apparatus of FIGS. 1A and 1B.

FIGS. 3A-3C are cross-sectional views of a patient's body including astenosis within a blood vessel, showing a method for dilating thestenosis using the apparatus of FIGS. 1A and 1B.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Turning to the drawings, FIGS. 1A and 1B show an exemplary embodiment ofan apparatus 10 for flaring and/or otherwise expanding a stent or otherprosthesis (not shown), e.g., within or adjacent an ostium or otherbifurcation between a main lumen and a branch lumen (also not shown).Generally, the apparatus 10 includes a catheter or other elongatetubular member 12 having a proximal end 14, a distal end 16, and one ormore lumens 18 extending between the proximal and distal ends 14, 16,thereby defining a longitudinal axis 20 extending between the proximaland distal ends 14, 16.

As shown, the catheter 12 may include a pair of overlapping balloons orother expandable members 22 on the distal end 16, e.g., for flaringand/or otherwise expanding a stent previously deployed within a bodylumen (not shown), as described further below. In addition, the distalend 16 may include one or more markers, e.g., one or more bands ofradiopaque material 19, to facilitate positioning the catheter 12relative to a stent and/or anatomical structures within a patient'sbody. In addition or alternatively, the catheter 12 may include one ormore therapeutic and/or diagnostic elements (not shown) on the distalend 16, e.g., within or carried by the balloon(s) 22, as describedfurther below.

Optionally, the apparatus 10 may be provided as a kit or systemincluding one or more additional components, such as syringes 11, aguide catheter, and/or one or more guidewires (not shown).

The catheter 12 may be formed from one or more tubular bodies, e.g.,having variable flexibility along its length. For example, the distalend 16 may be substantially flexible to facilitate introduction throughtortuous anatomy, e.g., terminating in a rounded, tapered, and/or othersubstantially atraumatic distal tip 17. The distal end 16 may be sizedand/or shaped for introduction into a body lumen, e.g., having adiameter between about one and seven millimeters (1-7 mm), or less than1.7 millimeters. The proximal end 14 may be substantially flexible,semi-rigid, or rigid, e.g., having sufficient column strength tofacilitate advancing the distal end 16 through a patient's vasculatureby pushing on the proximal end 14. Optionally, a shaft support wire orother stiffener (not shown) may be provided within the proximal end 14,if desired, e.g., to facilitate pushing the catheter 12 from theproximal end 14. The catheter 12 may be formed from plastic, metal, orcomposite materials, e.g., a plastic material having a wire, braid, orcoil core, which may preventing kinking or buckling of the catheter 12during advancement.

As shown in FIG. 1A, the catheter 12 may include a handle 30 on theproximal end 14, e.g., to facilitate manipulating the catheter 12. Thehandle 30 may include one or more ports 32 communicating with respectivelumens 18 within the catheter 12, as described further below. The handle30 may be molded, machined, or otherwise formed from plastic, metal, orcomposite material, e.g., providing an outer casing, which may becontoured or otherwise shaped to ease manipulation. The proximal end 14of the catheter 12 may be attached to the handle 30, e.g., by bonding,cooperating connectors, interference fit, and the like. Optionally, ifthe apparatus 10 includes any actuatable components (not shown) on thedistal end 16, the handle 30 may include one or more actuators (also notshown), such as one or more slides, dials, buttons, and the like, foractuating or otherwise manipulating the components from the proximal end14.

In the exemplary embodiment shown in FIG. 1B, the catheter 12 includesat least three lumens 18 extending between the proximal and distal ends14, 16. For example, the catheter 12 may include inflation lumens 18 a,18 b that extend from ports 32 a, 32 b in the handle 30 through thecatheter 12 to openings 34 a, 34 b and communicate within interiors 23a, 23 b of respective balloons 22 a, 22 b. The ports 32 a, 32 b on thehandle 30 may include connectors, e.g., a luer lock connector (notshown), one or more seals (also not shown), and the like. A source ofinflation media and/or vacuum, e.g., one of the syringes 11 filled withsaline or other inflation media, may be connected to the ports 32 a, 32b, e.g., directly or via tubing (also not shown), for expanding and/orcollapsing the balloons 22 a, 22 b.

In addition, the catheter 12 may include an instrument lumen 18 c thatextends from port 32 c to an opening 34 c in the distal tip 17. Theinstrument lumen 18 c may have sufficient size to allow a guidewire orother rail or instrument (not shown) to be inserted therethrough, e.g.,to facilitate advancing the catheter 12 over the rail, as explainedfurther below. Alternatively, rather than a “rapid exchange” instrumentlumen 18 c, an instrument lumen (not shown) may be provided that extendsfrom the handle 30 to the distal end 16. In this alternative, the handle30 may include a port (not shown) and/or one or more seals (also notshown) that prevent fluid, e.g., blood, from flowing proximally out ofthe port, yet allow one or more instruments to be inserted therethroughand into the instrument lumen 18 c.

As shown in FIG. 1B, the lumens 18 are disposed adjacent one another.Alternatively, the lumens 18 may be disposed in concentric or otherarrangements within the body of the catheter 12. In addition, if theapparatus 10 includes additional balloons (not shown) on the distal end16, the catheter 12 may include one or more additional inflation lumens(also not shown), and the handle 30 may include one or more additionalports (also not shown).

Alternatively, other configurations of lumens may be provided fordelivering fluid to and/or aspirating fluid from one or both balloons22. For example, a single lumen may be provided (not shown) thatcommunicates with the interiors 23 of both balloons 22. This embodimentmay allow the balloons 22 to be expanded and/or collapsed substantiallysimultaneously using a single syringe or other source of fluid/vacuum.In another alternative, the catheter 12 may include separate inflationlumens 18 a, 18 b, but the handle 30 may include a single side port (notshown) to which a syringe or other source of fluid/vacuum may beconnected. In this alternative, the handle 30 may include a switch,stopcock, valve, or other device (not shown) for selectively connectingone or both inflation lumens 18 a, 18 b to the side port, similar toembodiments in the applications incorporated by reference herein.

Returning to FIGS. 1A and 1B, the catheter 12 includes a first or innerballoon 22 a and a second or outer balloon 22 b on the distal end 16,which are expandable independently of one another. The balloons 22 maybe bonded or otherwise secured to the distal end 16 of the catheter 12,e.g., by bonding with adhesive, sonic welding, using an annular collaror sleeve, and the like. For example, as best seen in FIG. 1B, the innerballoon 22 a may include a proximal end 24 a attached directly to thedistal end 16 of the catheter 12 distal to instrument lumen port 32 cand a distal end 26 a attached directly to the distal end 16 adjacentthe distal tip 17.

The outer balloon 22 b includes a first or distal section 25 b thatextends at least partially over the inner balloon 22 a and a second orproximal section 27 b. For example, the first section 25 b may extendentirely over the inner balloon 22 a and a distal end 26 b of the outerballoon 22 b may be attached over or adjacent to the distal end 26 a ofthe inner balloon 22 a, e.g., by bonding, sonic welding, and the like,as described elsewhere herein. A proximal end 24 b of the outer balloon22 b may be attached to the distal end 16 of the catheter 12, e.g.,proximal or adjacent to the inner balloon proximal end 24 a and distalto the instrument lumen port 32 c.

The first section 25 b of the outer balloon 22 b may overlie but remainseparate from the underlying inner balloon 22 a. Alternatively, thefirst section 25 b may be bonded or otherwise attached to the innerballoon 22 a, e.g., continuously or intermittently along the innerballoon 22 a. Alternatively, the orientation of the outer balloon 22 bmay be reversed, if desired, e.g., with the second section 25 b of theouter balloon 22 b extending distally relative to the main section 25 aof the inner balloon 22 a rather than proximally. In a furtheralternative, a substantially spherical or bulbous section may beprovided on the outer balloon 22 b both proximally and distally to themain section 25 a of the inner balloon 22 a (not shown). In thisalternative, the proximal and distal sections may be expandedsimultaneously or independently of one another, as desired.

The inner balloon 22 a may be expandable from a contracted condition(not shown) to an enlarged condition (shown in FIGS. 1A and 1B).Similarly, the outer balloon 22 b may also be expandable from acontracted condition (not shown) to an enlarged condition (shown inFIGS. 1A and 1B). One or both balloons 22, e.g., inner balloon 22 a, maybe formed from substantially inelastic material, e.g., PET, nylon, orPEBAX, such that the balloon 22 expands to a predetermined size in itsenlarged condition once sufficient fluid is introduced into the interiorof the balloon 622. In addition or alternatively, one or both balloons22, e.g., outer balloon 22 b, may be formed from substantially elasticmaterial, e.g., silicone, polyurethane, or polyethylene, such that theballoon 22 may be expanded to a variety of sizes depending upon thevolume and/or pressure of fluid within the interior. In an exemplaryembodiment, the inner balloon 22 a may be formed from a semi-compliantor substantially non-compliant material, e.g., mid to high durometerPEBAX, nylon, or PET, and the outer balloon 22 b may be formed from asubstantially complaint or semi-compliant material, e.g., polyethylene,polyurethane, and low to mid durometer PEBAX.

To provide the proximal and distal sections 27 b, 25 b of the outerballoon 22 b, the balloon material may be formed into a shape includinga substantially spherical or other bulbous shape for the proximalsection 27 b and a substantially uniform, smaller diameter shape for thedistal section 25 b. For example, the balloon material may be blowmolded within a mold having the desired shape for the outer balloon 22 bwhen inflated. Because of the compliance of the balloon material, theouter balloon 22 b, e.g., the proximal section 27 b, may be expandedgreater than the relaxed molded shape, yet may substantially maintainthat shape unless constrained by external forces.

The outer balloon 22 b may have a substantially uniform wall thickness,e.g., between the proximal and distal sections 27 b, 25 b.Alternatively, the wall thickness may vary; for example, the proximalsection 27 b may have a thinner wall thickness than the distal section25 b. Optionally, the outer balloon 22 b may include one or morefeatures thereon for enhancing traction, friction, or other engagementwith structure contacted by the outer balloon 22 b when expanded. Forexample, the outer surface of at least the proximal section 27 b may betreated or textured, may include ribs or other protrusions, and the like(not shown) to increase friction or other engagement upon expansion.

In addition or alternatively, the balloons 22 may operate underdifferent internal pressures and/or may require different pressuressufficient to fully expand the respective balloons 22. For example, theinner balloon 22 a may require a greater inflation pressure to fullyexpand than the outer balloon 22 b. This may allow the proximal section27 b of the outer balloon 22 b to be expanded using a lower inflationpressure to flare and/or shape a flaring portion of a stent withoutsubstantial expansion of a main portion of the stent, as describedfurther elsewhere herein and in the applications incorporated byreference herein.

Alternatively, during use, the outer balloon 22 b may be inflated basedupon delivering one or more predetermined volumes of fluid therein,e.g., in multiple stages of expansion, as described further below. Forexample, the proximal section 27 b of the outer balloon 122 a may beinflated upon delivering a first predetermined volume of fluid thereinto flare the stent, e.g., between about 0.25-2 cubic centimeters orbetween about 0.5-4.2 cubic centimeters. Volume-based delivery may beuseful for describing the function of the outer balloon 22 b because ofits relative compliance and/or low pressure requirements, as explainedin the applications incorporated by reference herein.

As shown in FIGS. 1A and 1B, the proximal section 27 b of the outerballoon 22 b may be shaped to expand to a substantially spherical shapein the enlarged condition, e.g., having a diameter between about ten andtwenty millimeters (10-20 mm) when expanded using an inflation pressurebetween about one and five atmospheres (1-5 ATM). In an exemplaryembodiment, the proximal section 27 b of the outer balloon 22 b may havea diameter of about thirteen millimeters (13 mm) at an inflationpressure of about two atmospheres (2 ATM). In contrast, the innerballoon 122 b may be shaped to expand to a substantially cylindricalshape in the enlarged condition, e.g., having a diameter between abouttwo and eight millimeters (2-8 mm) when expanded using an inflationpressure between about eight and twenty atmospheres (8-20 ATM).

In addition, a main section 25 a of the inner balloon 22 a may have asubstantially uniform diameter, e.g., having a length between abouteight and thirty millimeters (8-30 mm). Beyond the uniform diameterportion, the inner balloon 22 a may have a transition portion 27 aadjacent the distal tip 17. The transition portion 27 a may be tapered,as shown, or may be substantially blunt, i.e., extending inwardly to thedistal tip 17 (not shown). As shown, the main portion 25 a of the innerballoon 22 a may underlie at least a portion of the outer balloon 22 b,e.g., the distal section 25 b, as shown in FIG. 1B and as disclosed inthe applications incorporated by reference elsewhere herein. In anexemplary embodiment, the main section 27 a of the inner balloon 22 amay have a diameter of between about five and six millimeters (5-6 mm)in the enlarged condition and may have a length of at least aboutseventeen millimeters (17 mm) distally beyond the proximal section 27 bof the outer balloon 22 b.

Optionally, the balloons 22 may include one or more diagnostic and/ortherapeutic elements. For example, in one embodiment, the outer balloon22 b may carry one or more therapeutic agents, e.g., at or adjacent thetransition zone between the proximal and distal sections 27 b, 25 b. Thetherapeutic agent(s) may be pressed against the wall of a vessel, e.g.,at an ostium, lesion, or within a branch, as described further below.

In another embodiment, one or more electrodes or other elements (notshown) may be provided on the balloons for delivering energy to tissuecontacted by the balloons 22. For example, one or more electrodes may beprovided on the outer balloon 22 b, e.g., at or adjacent the transitionzone between the proximal and distal sections 27 b, 25 b. Alternatively,one or more ultrasound elements may be provided on the distal end 16,e.g., on an inner surface of the outer balloon 22 b, on the innerballoon 22 a, and/or on the distal end 16 itself within the balloons 22.In this alternative, the inflation media used to expand the balloons 22may be selected that easily transmits ultrasonic energy to facilitateapplication of ultrasound to tissue surrounding the balloons 22. Inthese options, the handle 30 may include one or more actuators (notshown) for selectively activating and deactivating the energy element(s)on the distal end 16. In addition or alternatively, one or moreconnectors (also not shown) may be provided on the handle 30 forcoupling the energy element(s) to a driver, controller, or other sourceof electrical, ultrasound, or other energy (not shown).

Turning to FIGS. 2A-2F, an exemplary method is shown for using theapparatus 10 to flare and/or otherwise expand a stent 40 deployed withina patient's body, e.g., including an ostium 90. As shown, the ostium 90may be an opening in a wall of a first or main body lumen or trunk 92that communicates with a second body lumen or branch 94. In exemplaryembodiments, the main body lumen 92 may be the ascending or descendingaorta, and the branch body lumen may be a coronary artery, a commoncarotid artery, or a peripheral artery. A stenosis, occlusion, or otherlesion 96 may exist at and/or adjacent to the ostium 90, e.g., extendingat least partially into the branch 94. The lesion 96 may includeatherosclerotic plaque or other material that partially or completelyoccludes blood or other fluid flow between the trunk 92 and the branch94.

Initially, as shown in FIG. 2A, a guidewire 98 or other rail may beintroduced from the trunk 92 through the ostium 90 into the branch 94,e.g., using conventional methods. For example, a percutaneous punctureor cut-down may be created at a peripheral location (not shown), such asa femoral artery, carotid artery, or other entry site, and the guidewire98 may be advanced through the patient's vasculature from the entrysite, e.g., alone or with the aid of a guide catheter (not shown). Forexample, a distal end of a guide catheter (not shown) may be advancedover the guidewire 98 into the trunk 92, e.g., until the distal end isdisposed adjacent or proximal to the ostium 90. The guide catheter maybe used to advance one or more instruments (such as any of the cathetersor other devices described herein) over the guidewire 98 and into thetrunk 92 and/or branch 94.

If the lesion 96 completely occludes the branch 94, the guidewire 98 maybe directed through the occlusion, or other devices (not shown) may beadvanced over the guidewire 98 or otherwise in conjunction with theguidewire 98 to create a passage through the lesion 96 for the guidewire98.

After the guidewire 98 is directed into the branch 94 beyond the lesion96, it may be desirable to at least partially dilate the lesion 96. Forexample, an angioplasty catheter (not shown) may be advanced through theguide catheter and/or over the guidewire 98 into and through the lesion96, whereupon a balloon or other element on the catheter may be expandedto at least partially dilate the lesion 96. If desired, other proceduresmay also be performed at the lesion 96, e.g., to soften, remove, orotherwise treat plaque or other material forming the lesion 96, beforethe stent 40 is implanted. After completing any such procedures, anyinstruments advanced over the guidewire 98 may be removed.

To deliver the stent 40, any delivery catheter and/or conventionalprocedure may be used. For example, a distal end of a delivery catheter(not shown) may be advanced over the guidewire 98 and/or through theguide catheter from the entry site into the trunk 92. For example, withthe distal end of the guide catheter against or adjacent the ostium 90,the distal end of the delivery catheter may be advanced from the guidecatheter, through the ostium 90, and into the branch 94. The deliverycatheter may be positioned such that the stent 40 extends into andthrough the lesion 96 and/or branch 94. The stent 40 may be expandedand/or otherwise deployed from the delivery catheter to place the stent40 across the lesion 96 and/or within the branch 94. For example, asshown in FIG. 2B, the stent 40 may be deployed such that a first end 42of the stent 40 extends at least partially into the ostium 90 and/or thetrunk 92, and a second end 44 of the stent 40 is disposed within thebranch 94 beyond the lesion 96.

As shown, the stent 40 may have a substantially uniform diametercross-section once deployed. For example, the stent 40 may be expandedto dilate and/or otherwise engage the lesion 96 and/or branch 94.Alternatively, the stent 40 may be partially expanded using the deliverycatheter, allowing the stent 40 to be further expanded by the apparatus10, as described below.

Turning to FIG. 2C, thereafter, the distal end 16 of the flaringcatheter 12 (with the balloons 22 in their contracted conditions) may beintroduced into the trunk 92 to flare and/or otherwise expand the stent40. For example, the delivery catheter may be removed, and the distalend 16 of the catheter 12 may be advanced over the same guidewire 98into the trunk 92. In the embodiment shown in FIG. 1B, a proximal end(not shown) of the guidewire 98 may be backloaded into the opening 34 cthrough the instrument lumen 18 c and out the port 32 c. The distal end16 may then be advanced over the guidewire 98 into the patient's bodyover the guidewire 98.

As shown in FIG. 2C, the distal end 16 may be advanced through the stent40 and ostium 90 at least partially into the branch 94. For example, thedistal end 16 may be positioned such that the inner balloon 22 a ispositioned within and/or beyond the stent 40, e.g., beyond the first end42, and the proximal section 27 b of the outer balloon 22 b ispositioned adjacent the ostium 90, e.g., within and/or proximal to thefirst end 42 of the stent.

Optionally, to facilitate positioning, the catheter 12 may be monitoredusing fluoroscopy or other external imaging, e.g., to observe andmonitor markers 19 (not shown, see FIG. 1B) on the distal end 16. Forexample, markers 19 a and 19 b may be located on the distal end 16 toidentify the ends of the substantially uniform main section 25 a of theinner balloon 22 a, while proximal marker 19 c may be located on thedistal end 16 to identify the proximal end 24 b and/or proximal section27 b of the outer balloon 22 b. Thus, with the markers 19, the innerballoon 22 a may be aligned with the distal end 44 and/or portion of thestent 40 within the branch 94 beyond the ostium 90 and the proximalsection 27 b of the outer balloon 22 b may be aligned with the first end42 of the stent 40 and/or the ostium 90, as desired.

Turning to FIG. 2D, with the catheter 12 positioned as desired, theinner balloon 22 a may be expanded, e.g., by coupling syringe 11 a toport 32 a (not shown in FIG. 2D) and delivering saline, nitrogen, orother inflation media into the interior 23 a via inflation lumen 18 a,to engage the stent 40 and/or wall of the branch 94. For example, theinner balloon 22 a may be expanded to engage both the second end 44 ofthe stent 40 and the wall of the branch 94 beyond the stent 40 toprevent substantial axial migration of the stent 40.

Thereafter, as shown in FIG. 2E, the proximal section 27 b of the outerballoon 22 b may be expanded, e.g., by coupling syringe 11 b to port 32b (not shown in FIG. 2E) and delivering saline, nitrogen, or otherinflation media into the interior 23 b via inflation lumen 18 b, toflare the stent 40. For example, as the proximal section 27 b isexpanded, the first end 42 of the stent 40 is expanded, e.g., into aflared configuration, which may conform to the shape of the proximalsection 27 b and/or the ostium 90.

With the inner balloon 22 a expanded, the stent 40 and catheter 12 mayremain substantially stationary during this inflation and flaring.Otherwise, without the inner balloon 22 a engaging the stent 40 and wallof the branch 94, there may be a tendency for the stent 40 to migratedistally into the branch 94 rather than flaring in place, e.g.,maintaining its substantially uniform diameter, which may shear orotherwise remove material from the lesion 96 and/or wall of the branch94 and potentially release the material within the branch 94. Inaddition or alternatively, without the inner balloon 22 a expanded,there may be a tendency of the distal end 16 of the catheter 12 to moveproximally away from the stent 40 and ostium 90. Thus, the inner balloon22 a may provide an anchor that ensures the first end 42 of the stent 40is flared in a desired manner with the stent 40 and catheter 16substantially fixed relative to one another and the ostium 90.

Optionally, after inflating the proximal section 27 b and flaring thefirst end 42 of the stent 40, the inner balloon 22 a may be inflatedfurther, if desired, e.g., to expand the stent 40 and further dilate thelesion 96. With the stent 40 fully deployed, the balloons 22 may bedeflated or otherwise collapsed, and the catheter 12 may be withdrawnfrom the branch 94 and trunk 92, and from the patient's body, e.g., intothe guide catheter (not shown). The guide catheter and/or guidewire 98may then be removed from the patient's body, leaving the stent 40 inplace, as shown in FIG. 2F.

In alternative embodiments, other inflation sequences may be used, asdesired, e.g., to initially deliver and deploy a stent and then flarethe stent, e.g., within an ostium 90. For example, after the stent 40has been deployed within the branch 94, the distal end 16 may beintroduced into the trunk 92. With the proximal section 27 b within thetrunk 92, the outer balloon 22 b may be partially inflated to expand theproximal section 27 b before advancing the distal end 16 into the branch94. When so advanced, the proximal section 27 b may partially seatwithin the ostium 90 and/or within the first end 42 of the stent 40.Alternatively, the distal end 16 may be positioned within the branch 94with the proximal section 27 b collapsed until the inner and/or outerballoons 22 a, 22 b are aligned as desired relative to the ostium 90and/or stent 40. Once positioned as desired relative to the ostium 90,lesion 96, and/or stent 40, e.g., by observing the markers 19 on thedistal end 16, the proximal section 27 b of the outer balloon 22 b maybe at least partially expanded, e.g., to engage the first end 42 of thestent 40 and/or the ostium 90. During this initial inflation, the firstend 42 may be flared or may not be expanded substantially. With theproximal section 27 b expanded, the distal end 16 may be substantiallyanchored relative to the stent 40 and branch 94, e.g., to preventmigration of the distal end 16.

The inner balloon 22 a may then be inflated to expand the stent 40and/or dilate the lesion 96. During such inflation, there is a tendencyfor the distal end 16 of the catheter 12 to migrate distally relative tothe stent 40 and lesion 96, which may risk causing a dissection distallybeyond the stent 40 (what is sometimes called “watermelon seeding”).However, with the proximal section 27 b expanded to engage the first end42 of the stent 40 and/or ostium 90, the distal end 16 may besubstantially anchored, thereby preventing such migration.

Once the stent 40 is expanded and/or the lesion 96 is dilated by theinner balloon 22 a, the outer balloon 22 b may be inflated further, ifdesired, e.g., to expand the proximal section 27 b and flare the firstend 42 of the stent 40. Thus, the inner and outer balloons 22 a, 22 bmay be alternately expanded one or more times, as desired, until thestent 40 achieves the desired final configuration.

In another alternative, after initially expanding the proximal section27 b of the outer balloon 22 b within the ostium 90 and/or first end 42of the stent, the inner balloon 22 a may be inflated to engage thesecond end 44 of the stent 40 and the wall of the branch 94 tosubstantially anchor the stent 40 and catheter 12 relative to oneanother without necessarily expanding the stent 40 further. The outerballoon 22 b may then be inflated further to expand the proximal section27 b and flare or otherwise shape the first end 42 of the stent 40relative to the ostium 90.

In still another alternative, the apparatus 10 may be used to expand astent previously placed within a substantially straight or othernon-bifurcated body lumen, such as within a carotid, iliac, renal,coronary artery, or other blood vessel. For example, the distal end 16of the catheter 12 may be introduced into the vessel until the innerballoon 22 a is aligned with the stent 40. The outer balloon 22 b maythen be inflated such that the proximal section 27 b engages a first endof the stent and/or the wall of the vessel adjacent the stent 40 tosubstantially anchor the stent 40, e.g., without dilating the stent 40and/or vessel. The compliant nature of the outer balloon 22 b mayfrictionally engage the vessel wall and/or the stent 40 to preventsubstantial migration, e.g., without applying a substantial dilatingforce. Optionally, at least the proximal section 27 b of the outerballoon 22 b may include a surface treatment and/or one or more featuresthat enhance frictional or other engagement with the vessel wall and/orstent 40.

Thereafter, the inner balloon 22 a may be inflated to expand the stent40 and/or dilate the lesion or body lumen surrounding the stent 40, asdesired, with the outer balloon 22 b preventing migration of the distalend 16 relative to the stent 40. The balloons 22 a, 22 b may then bedeflated and the distal end 16 removed from the stent 40 and/or vessel.

In a further alternative, a stent or other prosthesis, such as thosedisclosed in the applications incorporated by reference herein, may beprovided on the distal end 16 of the catheter 12. For example, a stent(not shown) may be delivered directly on the catheter 12, e.g., on oneor more both of the balloons 22 a, 22 b, rather than on a separatedelivery catheter, if desired, using similar methods to those describedherein and in the applications incorporated by reference herein.Alternatively, a delivery balloon (not shown) may be provided on thedistal end 16 of the catheter 12, e.g., proximal or distal to theballoons 22, and a stent may be introduced and deployed on the deliveryballoon into an ostial or substantially straight implantation site. Theballoons 22 a, 22 b may then be used to flare and/or expand the stentusing similar methods to those described above.

In still another alternative, the apparatus and methods herein may beused to treat a stenosis, occlusion, or other lesion 96 within a bodylumen 94 without a stent. For example, as shown in FIGS. 3A-3C, duringan angioplasty procedure, after positioning the main section 25 a of theinner balloon 22 a across a stenosis 96, the proximal section 27 b ofthe outer balloon 22 b may be inflated to substantially anchor thedistal end 16 relative to the body lumen 94. Alternatively, the outerballoon may be provided distal to the inner balloon or outer balloonsmay be provided both proximally and distally to the main section 25 a ofthe inner balloon (not shown), as described elsewhere herein.

The inner balloon 22 a may then be inflated to expand the main section25 a to dilate the stenosis 96, as desired. In this alternative, thebody lumen 94 may be a non-bifurcated body lumen or a body lumenincluding a branch extending from a trunk. In the latter example (notshown), the distal end 16 may be positioned within the branch, and theouter balloon 22 b may be inflated to expand the proximal section 27 bto dilate the ostium and/or stenosis therein before or after expandingthe main section 25 a of the inner balloon 22 a within the branch,similar to the methods described elsewhere herein.

In other alternatives, the apparatus and methods herein may be used fortreating other structures within a patient's body. For example, thecatheter 12 may be used to perform valvuloplasty on heart valves, e.g.,an aortic valve of a patient's heart. In this alternative, the mainsection 25 a of the inner balloon 22 a may be expandable to diameters ofat least nineteen millimeters (19 mm) or more, and the proximal section27 b of the outer balloon 22 b may be expandable to larger diameters,e.g., to substantially anchor the distal end 16 of the catheter 12 whilethe inner balloon 22 a is introduced into and expanded to treat thevalves, and/or to facilitate additional treatment. For suchapplications, the inner balloon 22 a may be formed from ultra-highpressure materials, such as single resin combinations of balloonmaterials, such as those described above in combination with PTFE,reinforced fiber composite materials, and/or metallic or polymericbraids, weaves, or other reinforcement structures, e.g., similar toballoons disclosed in U.S. Pat. No. 7,744,620, the entire disclosure ofwhich is expressly incorporated by reference herein.

During use, the inner balloon 22 a may be introduced through the site ofa natural or prosthetic valve, such as an aortic valve (not shown), andthe outer balloon 22 b may be expanded to prevent migration and/orotherwise stabilize the distal end 16 relative to the valves. The innerballoon 22 a may then be expanded to treat the valve, e.g., to dilatethe valve leaflets (not shown) of the valve. In one embodiment, theouter balloon 22 b may be located distal to the inner balloon 22 a suchthat the outer balloon 22 b is positioned within the left ventricle ofthe patient's heart, and the inner balloon 22 a may extend through thevalve annulus, e.g., into the coronary sinus. With the outer balloon 22b expanded within the left ventricle, the outer balloon 22 b may contactthe heart wall adjacent the aortic valve, thereby preventing the distalend 16 from migrating out of the heart into the aorta. The inner balloon22 a may be expanded one or more times and/or to one or more diametersto dilate the leaflets, e.g., to increase their flexibility and/orseparate plaque or other materials on the leaflets.

Optionally, a filter or other embolic protection device (not shown) maybe provided on the catheter 10, e.g., proximal to the balloons 22 a, 22b, or otherwise introduced into the coronary sinus or aorta of thepatient to capture any plaque or other material released during thetreatment. For example, an expandable filter (not shown) may be providedon the distal end 16 spaced apart proximally from the balloons 22 a, 22b, which may be expanded downstream to the aortic valve before expandingthe outer balloon 22 b and/or the inner balloon 22 a. After thetreatment, the filter may be collapsed to capture the released material,e.g., after collapsing the inner balloon 22 a and either before or aftercollapsing the outer balloon 22 b. The catheter 10 may be removed fromthe valve site.

Alternatively, the outer balloon 22 b may be provided proximal to theinner balloon 22 a. For example, the distal end 16 may be positionedsuch that the main section of the inner balloon 22 a is disposed withinthe valve annulus, e.g., with the outer balloon 22 b located adjacentthe leaflets, e.g., within the coronary sinus. The inner balloon 22 amay be expanded to initially dilate the leaflets of the valve, andthereafter, if desired, the outer balloon 22 b may be expanded tofurther dilate the leaflets, e.g., direct them outwardly towards oragainst the wall of the coronary sinus. For example, the inner balloon22 a may be expanded to a first diameter to at least partially dilatethe leaflets into the coronary sinus, and then the outer balloon 22 bmay be expanded to a second larger diameter to further dilate theleaflets. The inner and/or outer balloons 22 a, 22 b may be expanded andcollapsed one or more times, as desired to perform a desired treatmenton the valve.

In a further alternative, the outer balloon 22 b may be expanded withinthe coronary sinus or otherwise distal to the valve site beforeexpanding the inner balloon 22 a. The outer balloon 22 b may contactsurrounding tissue to prevent migration of the distal end 16 and/or toprevent plaque or other released material from traveling downstream.Optionally, a filter or other embolic protection device may be deployedproximal to the outer balloon 22 b, if desired, as described above. Theinner balloon 22 a may then be expanded one or more times to treat theleaflets, as described above, and then the balloons 22 a, 22 b may becollapsed and the catheter 10 removed from the valve site. Optionally,in this alternative, the catheter 10 may include an aspiration portadjacent the balloons 22 a, 22 b for aspirating released materialcaptured by the outer balloon 22 b.

It will be appreciated that elements or components shown with anyembodiment herein are exemplary for the specific embodiment and may beused on or in combination with other embodiments disclosed herein.

While the invention is susceptible to various modifications, andalternative forms, specific examples thereof have been shown in thedrawings and are herein described in detail. It should be understood,however, that the invention is not to be limited to the particular formsor methods disclosed, but to the contrary, the invention is to cover allmodifications, equivalents and alternatives falling within the scope ofthe appended claims.

We claim:
 1. A method for flaring a stent previously deployed within abranch body lumen including an ostium communicating with a main bodylumen, a first end of the stent extending at least partially from thebranch body lumen into the ostium, the method comprising: providing anelongate member including a proximal end, a distal end, an expandablemember carried on the distal end that includes a substantially uniformdiameter distal section, and a proximal section extending proximallyfrom the distal section, wherein at least the proximal section comprisescompliant material molded to a shape in which the proximal section has abulbous shape defining a first diameter and wherein the distal sectionhas a substantially cylindrical shape defining a second diameter smallerthan the first diameter; introducing the distal end into the main bodylumen; positioning the distal end of the elongate member through theostium and stent into the branch body lumen until the distal section isdisposed within the stent; initially expanding the expandable member toengage the distal section within the stent to substantially anchor thestent axially relative to the branch body lumen; and expanding theproximal section to flare the first end of the stent within the ostium.2. The method of claim 1, further comprising, after expanding theproximal section, further expanding the expandable member to expand thestent within the branch body lumen.
 3. The method of claim 2, whereinthe diameter of the branch body lumen does not increase substantiallywhen the expandable member is initially expanded to engage the distalsection within the stent, and wherein the branch body lumen is dilatedwhen the expandable member is further expanded to expand the stent. 4.The method of claim 1, wherein positioning the distal end of theelongate member comprises positioning the distal end of the elongatemember such that the proximal section is disposed adjacent the ostiumbefore initially expanding the expandable member.
 5. The method of claim4, further comprising monitoring markers on the distal end of theelongate member to facilitate positioning the proximal section adjacentthe ostium.
 6. The method of claim 1, wherein initially expanding theexpandable member prevents the stent from migrating substantially whenthe proximal section is expanded.
 7. The method of claim 1, wherein thematerial of the expandable member has a thinner wall thickness along theproximal section than along the distal section.
 8. The method of claim1, further comprising delivering energy from one or more elements on theexpandable member to surrounding tissue adjacent the stent.
 9. A methodfor treating a lesion within a branch body lumen including an ostiumcommunicating with a main body lumen, the method comprising: introducinga distal end of a delivery catheter into the main body lumen, thedelivery catheter distal end carrying a stent in a contracted condition;positioning the delivery catheter distal end within the branch bodylumen such that a first end of the stent is disposed adjacent the ostiumand a second end of the stent is disposed further within the branch bodylumen; expanding the stent such that the stent engages surroundingtissue of the branch body lumen; removing the delivery catheter from thebranch body lumen and main body lumen; introducing a distal end of aflaring catheter into the main body lumen, the flaring cathetercomprising a proximal end, a distal end, an expandable member carried onthe flaring catheter distal end that includes a substantially uniformdiameter distal section when expanded, and a proximal section extendingproximally from the distal section; wherein at least the proximalportion comprises compliant material molded to a shape in which theproximal section has a bulbous shape defining a first diameter and thedistal section has a substantially cylindrical shape defining a seconddiameter smaller than the first diameter; positioning the flaringcatheter distal end through the ostium and stent into the branch bodylumen until the distal section is disposed within the stent; initiallyexpanding the distal section to substantially anchor the stent axiallyrelative to the branch body lumen; and thereafter, continuing expandingthe proximal section to flare the first end of the stent within theostium.
 10. The method of claim 9, wherein the lesion is dilated whenthe stent is initially expanded on the delivery catheter to asubstantially uniform diameter.
 11. The method of claim 10, furthercomprising, after expanding the proximal section, further expanding theexpandable member to expand the distal section to expand the stentfurther within the branch body lumen and dilate the lesion further. 12.The method of claim 9, further comprising, after expanding the proximalsection, further expanding the expandable member to expand the stentwithin the branch body lumen.
 13. The method of claim 12, wherein thediameter of the branch body lumen does not change when the expandablemember is initially expanded, and wherein the branch body lumen isdilated when the expandable member is further expanded to expand thestent.
 14. The method of claim 9, further comprising introducing adistal end of a guidewire into the main body lumen and through theostium into the branch body lumen, and wherein the delivery catheterdistal end is introduced into the main body lumen and positioned withinthe branch body lumen over the guidewire.
 15. The method of claim 14,wherein the flaring catheter distal end is introduced into the main bodylumen over the guidewire after removing the delivery catheter.
 16. Themethod of claim 9, wherein positioning the distal end of the flaringcatheter comprises positioning the flaring catheter distal end such thatthe proximal section is disposed adjacent the ostium before initiallyexpanding the expandable member.
 17. The method of claim 16, furthercomprising monitoring markers on the flaring catheter distal end tofacilitate positioning the proximal section adjacent the ostium.
 18. Themethod of claim 9, wherein initially expanding the expandable memberprevents the stent from migrating substantially when the proximalsection is expanded.
 19. The method of claim 9, further comprisingdelivering energy from one or more elements on the expandable member tosurrounding tissue adjacent the stent.
 20. The method of claim 9,wherein the proximal section has a thinner wall thickness than a wallthickness of the distal section.
 21. A method for expanding a stentpreviously deployed within a body lumen, comprising: providing anelongate member including a proximal end, a distal end, an expandablemember carried on the distal end that includes a substantially uniformdiameter distal section when expanded, and a proximal section extendingproximally from the distal section; wherein at least the proximalsection is formed from compliant material molded to a shape in which theproximal section has a bulbous shape defining a first diameter and thedistal section has a substantially cylindrical shape defining a seconddiameter smaller than the first diameter; positioning the distal end ofthe elongate member within the body lumen until the main section isdisposed within the stent; expanding the proximal section tosubstantially anchor the distal end relative to the stent; and afterexpanding the proximal section, expanding the distal section to expandthe stent.
 22. The method of claim 21, wherein the body lumen comprisesa non-bifurcated body lumen.
 23. The method of claim 22, wherein thebody lumen comprises a branch body lumen including an ostiumcommunicating with a main body lumen, wherein the stent is deployedwithin the branch body lumen, and wherein positioning the distal end ofthe elongate member comprises positioning the distal end of the elongatemember through the ostium and stent into the branch body lumen until themain section is disposed within the stent.
 24. A method for treating astenosis within a body lumen, comprising: providing an elongate memberincluding a proximal end, a distal end, an expandable member carried onthe distal end that includes a substantially uniform diameter distalsection when expanded, and a proximal section extending proximally fromthe distal section, wherein at least the proximal section is formed fromcompliant material molded to a shape in which the proximal section has abulbous shape defining a first diameter and the distal section has asubstantially cylindrical shape defining a second diameter smaller thanthe first diameter; positioning the distal end of the elongate memberwithin the body lumen with the expandable member collapsed until thedistal section is disposed within the stenosis; expanding the proximalsection to substantially anchor the distal end relative to the stenosis;and after expanding the proximal section, continuing expanding thedistal section to dilate the stenosis.
 25. The method of claim 24,wherein the body lumen comprises a non-bifurcated body lumen.
 26. Themethod of claim 24, wherein the body lumen comprises a branch body lumenincluding an ostium communicating with a main body lumen and having thestenosis therein, and wherein positioning the distal end of the elongatemember comprises positioning the distal end of the elongate memberthrough the ostium and stenosis into the branch body lumen until thedistal section is disposed within the stenosis.